1. Field of the Invention
The present invention relates to digital image processing and, more particularly, to decompressing interpolated images.
2. Description of the Related Art
In many image processing pipelines a compromise has to be made between the number of bits used to store an image and the distortion introduced by compressing it. Although lossless compression schemes can achieve some saving of the storage required, for larger compression ratios it is usually necessary to use a lossy compression method. Many lossy compression schemes are known, JPEG (Joint Photographic Experts Group) is typical of such schemes. See, for example, the baseline version of the JPEG algorithm (ITU-T Rec.T.81/ISO/IEC 10918-1 "Digital Compression and Coding of Digital Still Images").
Although lossy coders are typically designed so that the loss introduced is as imperceptible as possible, there will always be artifacts of the compression and these become increasingly objectionable as the compression ratio is increased. Sometimes it is possible to improve the compressed image, for example by attempting to remove the blocking artifacts of JPEG (see, for example, R. Eschbach, Decompression of Standard ADCT-compressed Images, U.S. Pat. No. 5,379,122, January 1995), but in general there is limited room for improvement of compressed images.
Thus, it can be seen that lossy image compression techniques impose image fidelity limits upon image capture or display devices, and hinder the use of these devices in many applications.
Therefore, there is an unresolved need for an image decompression technique that can improve the fidelity of decompressed lossy-compressed interpolated images by decreasing the error introduced for a given compression ratio.